Numbers of the form 2^k or 7*2^k.

Terms

a(0) =1a(1) =2a(2) =4a(3) =7a(4) =8a(5) =14a(6) =16a(7) =28a(8) =32a(9) =56a(10) =64a(11) =112a(12) =128a(13) =224a(14) =256a(15) =448a(16) =512a(17) =896a(18) =1024a(19) =1792a(20) =2048a(21) =3584a(22) =4096a(23) =7168a(24) =8192a(25) =14336a(26) =16384a(27) =28672a(28) =32768a(29) =57344